The imbibition printing dye transfer process is well known. According to common procedures, a tanned colloid relief image is formed by imagewise exposure of a suitable light sensitive layer on a support, differentially hardening the colloid layer in accordance with the imagewise exposure, and removing the colloid from the support in inverse proportion to the amount of imagewise light exposure. The differential colloid hardening and removal is conventionally performed with a pyrogallol hardening developer as described, e.g., in U.S. Pat. No. 2,837,430, the disclosure of which is hereby incorporated by reference. For full color prints, three separate relief images corresponding to the blue, green, and red color records of the image being reproduced may be formed in separate blue, green, and red light sensitive matrix films by three separate exposures though a color negative film. The resultant colloid relief images are then dyed with yellow, magenta and cyan dyes, and the dye images transferred to a imbibition printing blank receiver film. In this manner imbibition printed colored dye images may be obtained which faithfully reproduce a colored subject. Imbibition printing blanks comprise a dye receiving layer on a support. Where the resulting image is intended to be viewed by light projection, such as in a motion picture film, a transparent film support is generally used.
U.S. Pat. Nos. 3,625,694; 3,958,995; and 3,898,088 disclose cationic (basic) mordants which may be used in dye imbibition printing blanks. Such mordants are suitable for use with anionic (acid) printing dyes. When using blanks containing a dye receiving layer comprising a cationic mordant and a hydrophilic colloid such as gelatin as a binder, there is a tendency for the blank to be brittle resulting in cracking and degradation of the transferred dye image.
The necessity for maintaining flexibility in film is obvious in view of the handling to which it is subjected in manufacturing and use. For example, films are flexed and bent during use in cameras, printers, projectors, and processing equipment. The brittleness of film is affected by both temperature and relative humidity, the latter being generally of greater practical importance. Below approximately 25 percent relative humidity, a significant change in film brittleness may occur with only a small change in relative humidity. The failures in film as a result of lack of flexibility may be of different types, depending upon the nature of the stress.
It has been suggested to include plasticizers in imbibition printing blanks and photographic elements to reduce brittleness. U.S. Pat. Nos. 2,882,156 and 3,709,690 disclose blanks containing mordants and polymer latices as plasticizers. U.S. Pat. No. 5,135,835 relates to heat developable photographic elements which contain a mordant, oil droplets and a polymer latex having a glass transition temperature (Tg) of 40.degree. C. or less for improving brittleness.